I like this. I'm using it as soon as I installed it, and relying on it within minutes.
I hope you don't mind my proposing some ideas:
- the closed state doesn't stick over page-loads; have you considered cookies or ez preferences?
- being able to completely hide the toolbar and call it up with a key-press, like ctrl-spacebar
- being able to enable only for logged-in users (so that one could install it on a production site)
- the default location is somewhat in the way - that is where the first of my echo-output goes
